Soldering agent



Patented Sept. 12, 1939 2,172,979

UNITED STATES PATENT OFFICE 2,172,979

SOLDERING AGENT FrittKiihler, Eduard Rouette, and Wilhelm Standop, Bonn-on-the-Rhine, Germany No Drawings Application April 1, 1939, Serial No. 265,546. In Germany April 28, 1938 6 Claims. (Cl. 148-23) This invention relates to an improvement in, wh using th mixture according t t i or modification of, the soldering agent for the v nti n, after th complex salt has removed the soft soldering of aluminium and aluminum alloys oxide skin an alloy of tin and zinc separates out which is described and claimed in U. S. Patent b interchange a ti n with the aluminum which 2,155,307. makes the soldered joint. The aluminum halide 5 This patent relates to Soldering agent for or magnesium halide forming during the intersoft soldering aluminum which consists of the action is taken up by the undecomposed complex p e Combination o a y o de of a hy salt and is completely vapourised with the same. drogen-rich organic amine base with a halide Consequently no slag containing aluminum 10 10 of tetravalent tin. This soldering agent has the halide or magnesium halide remains at the solderat advantage Over Simple ydrohalides of ing place, so that corrosion as a result of such hydrogen-rich Organic mine bases that it is exsalt residues is excluded. The magnesium halide, traordinarily stable towards moisture of the air, more particularly magnesium chloride, therefore 1 since the halogen in this combination is split oil in the case of the soldering agent according to 11013 s en ion, which decomposes the zinc-of the invention no longer checks the soldering the solder dust to zinc halide, but in the form operation in the form of a solid separation as in of the ion of a tin halogen acid which behaves the case of the known soldering mixtures and inactively towards the metal dust of an aluminum does not prevent the diffusion of the soldering soft solder paste. metal formed into the surface of the alloy.

A11 hydrohalides, that s to say the hydrochlo- The mixture according to the invention, which 2 0 ride, hydrobromide, hydroiodide and hydrofluomay contain water-sensitive salts such as stanride, of the hydrogen-rich organic amine bases nous chloride and zinc chloride, may in such cases come into question as components of the complex be protected from the influence of the atmossalt formation, as well as all four stannic halides phere by rubbing up the mixture with a water- (stannic chloride, stannic bromide, stannic iodide, repelling organic oil, such as parafiin oil, Vaseline 25 stannic fluoride). or the like.

For example, an amine base hydrobromide may The mixture proportions between zinc halide be united with stannic bromide to form the base and stannous halide may be varied within wide salt of bromstannic acid, that is to say a brom limits without impairing the emciency of the stannate, or it may be united with stannic chlosoldering agent. For example a ratio of zinc 30 ride, stannic iodide or stannic fiuoride,when comchloride to stannous chloride equal to 14.52855 plex salts of mixed halogen stannic acids are parts by weight has proved to be particularly formed, that is to say abase dibromotetrachlorofavourable because from such a mixture the stannate, or a dibromotetraiodo-stannate, etc. eutectic tin-zinc alloy with the lowest melting The complex salt formation maybe demon: point separates out. I 35 strated by the following scheme: The soldering agent provided by the invention UX) aNHhsnymz solders even aluminum alloys with compara- 40 and Y and Z are any desired halogen 'atoms. Of e tively high magnesium contents without the smallest difliculty.

In the following examples all the parts are 40 parts by weight.

in which X is a hydrogen-rich organic residue,

course Y and Z may also be the same halogen atoTmhs. 1 It t t d h Example I x e comp ex sa s 1115 men lone ave a very low melting point and have an extraordinary 33 parts of tnethwamme'cmomstannate' strong solvent action on aluminum oxide. The 67 ,parts of mlxture of parts f mm 45 tin contained in them they deposit during the chloride and 85.5 parts of stannous chloride.

soldering operation and form tinned surfaces on According to a further characteristic of the he ar aluminumpresent invention the mixture according to the It has now been found that if one of the said invention may also have added thereto decomplex salts is mixed withanhydrous tin dihydrated halides of metals which are more noble 50 halide, more particularly stannous chloride, andthan the aluminum, or magnesium-containing zinc halide, more particularly zinc chloride, suraluminum, to be soldered. For example lead prisingly enough a soldering agent is obtained chloride (PbClz), cadmium chloride (CdCh), which'is outstandingly suitable for the solderantimony trichloride (SbCla) and bismuth triing of magnesium-containing aluminum alloys. chloride (BiCls) have proved to be suitable. 5

By means of the additions Just mentioned, it is possible to vary the position oi the melting point for example of the reduced metal within wide limits, hich is very advantageous in many cases.

Example I! parts of triethylamine-chlorostannate are intimately rubbed with parts oi! the following four mixtures:

1 Parts Stannous chloride 85.5 Zinc chloride 7.5 Lead chloride (PbClz) 7.0

Stannous chloride 85.5 Zinc chloride 7.5 Cadmium chloride -4 7.0

3 Stannous chloride 85.5 Zinc chloride 7.5 Antimony trichloride 7.0 4. Stannous chloride 85.5 Zinc chloride, 7.5 Bismuth trichloride 7.0

What we claim is: 1. A soldering composition for the soft soldering of aluminum and particularly magnesium aluminum alloys comprising a complex salt containing a stannic halide and hydrohalide of a hydrogen rich amine base in reactive combination with at least one stannous halide and at least one zinc halide, said complex salt being adapted to form during the soldering procedure a vaporizable compound and a joint creating tinzinc alloy with the light metal halide produced by the action of said complex salt upon the light metal.

2. A soldering composition according to claim 1 characterized therein that in using stannous chloride and zinc chloride the ratio of these two substances is 85.5 to 14.5 parts by weight.

3. A soldering composition according to claim 1 characterized by the addition of a water repelling organic oil and preferably paraflln oil or Vaseline.

4. In a soldering composition according to claim 1 the complex salt being triethylamino chlorostannate.

5. A soldering composition according to claim 1 characterized by the further addition of at least one dehydrated halide of a metal selected from the group consisting of lead, cadmium, antimony and bismuth.

6. A soldering composition according to claim 1 in which the complex salt is triethylamino chlorost-annate and in which at least one dehydrated halide of a metal selected from the group consisting of lead, cadmium, antimony and bismuth is further added. I

FRITZ KGHLER. EDUARD ROUETI'E. WILHEIM STANDOP. 

